Thursday, May 25, 2017

How Does a Flamingo Stand on One Leg?

The Science Behind the Flamingo’s One-Legged Stance

An Andean flamingo in Chile’s
Antofagasta region. A new study provides insight into the mechanics of
the birds’ one-legged stance.Credit
DeAgostini/Getty Images

Squat
down as if you’re going to sit in a chair. Make sure to keep your back
straight, use your hips as a hinge and push your butt backward. Try not
to lean forward. Maintain your knees and ankles at 90-degree angles. Now
try it on just one leg, and then swap that one with the other. To make
it even harder, stand on a foam mat — and close your eyes.

You may feel your body wobbling, or you may fall over. If only you were a flamingo.

Flamingos can stand on one leg for a really long time. They even do it while sleeping. And according to a study published Tuesday in Biology Letters, flamingos may not even need to use their muscles for the task.

“It’s not tiring for them to stand on one leg and they can achieve it with very little effort,” said Lena Ting,
a biomedical engineer at Emory University and the Georgia Institute of
Technology who co-led the study. “It might even be easier for them to
stand on one leg than to stand on two.”

Plenty
of birds adopt a one-legged posture, often while sleeping, but the
flamingo provides an extreme example. The prevailing hypotheses say the
birds do it either to reduce muscle fatigue caused by switching legs, or
to conserve heat. But both assume it takes muscles to stand this way,
and that hadn’t actually been tested.

Dr. Ting and her colleague, Young-Hui Chang,
a neuromachinist at Georgia Tech who works with prosthetics, analyzed
the behavior of flamingos in a zoo and examined the joints of flamingo
cadavers.

With
the help of zoo keepers, the researchers coaxed eight young flamingos
who had just eaten and were getting sleepy onto a device called a force
plate to measure their postural sway, or the movements of an unsteady
body as it tries to stabilize itself.

Researchers coaxed a baby flamingo onto a force plate to measure how it stabilizes itself while standing on one leg.Credit
Rob Feit/Georgia Tech

“Remarkably,
when they’re falling asleep, the motion and the speed of the body was
very, very low,” said Dr. Ting. “That’s counterintuitive because when
you and I stand on one leg and close our eyes, we generally have more
postural sway.”

That’s
because our response is complicated. The nervous system senses
instability and sends messages to muscles to tell them to contract to
stabilize the body. But the steady zoo flamingos appeared to use some
kind of passive strategy that relied less on muscles and nerves, and
more on the simple mechanics of how their bodies fit together.

The
researchers used flamingo cadavers, which obviously lack active
muscles, to see if muscles were necessary for this stability.

Dr.
Chang stood the cadavers up in a one-legged position. Rather than
flopping over as expected, the bird settled into a stable, one-legged
posture that stayed put even when the top of its body was tilted
backward and forward. On two legs, or if the foot was not right below
the body, the cadaver was far less stable.

The
joints were easily unfolded also, suggesting that a flamingo can
transition out of this position without much effort, either to switch
legs, respond to wind or muddy water, or escape a threat.

The
birds showed that “it’s possible to maintain what we’d consider very
difficult posture without having to activate muscles,” said Dr. Ting.
The birds might, she added, rely on gravity and some interaction between
joints and ligaments to keep everything in place.

Because
moving in and out of the one-legged stance appears to use little
energy, flamingos could inspire improvements for robotics and powered
prosthetics, said Dr. Ting, who studies the process of recovering
movement after an injury.

“Usually
as humans we take the standing behavior for granted until we lose that
ability,” she said. Simplicity may be for the birds, but we complicated
humans can appreciate its lessons.

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This is a blog about what interests me. Here you will find stories on animals, including animal rights material, cute stuff, and random informative posts about weird, beautiful and interesting creatures. Horses, Spotted Hyenas, and Border Collies will make regular appearances.
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